A core Expression that controls the enabled of the given auto edit strategies. The viewer, editor, and editor input are registered in the evaluation context as variable:
* : use it if your expression requires the viewer.
* : use it if your expression requires the document.
* : use it if your expression requires the editor (deprecated, not always set).
* : use it if your expression requires the editor input (deprecated, not always set).

This element is used to perform an instanceof check of the object in focus. The expression returns
EvaluationResult.TRUE if the object's type is a sub type of the type specified by the attribute value.
Otherwise EvaluationResult.FALSE is returned.

This element is used to evaluate the property state of the object in focus. The set of testable properties can be extended using the org.eclipse.core.expressions.propertyTesters extension point. The test expression returns EvaluationResult.NOT_LOADED if the property tester doing the actual testing isn't loaded yet and the attribute forcePluginActivation is set to false. If forcePluginActivation is set to true and the evaluation context used to evaluate this expression support plug-in activation then evaluating the property will result in activating the plug-in defining the tester.

property - the name of an object's property to test.

args - additional arguments passed to the property tester. Multiple arguments are separated
by commas. Each individual argument is converted into a Java base type using the same
rules as defined for the value attribute of the test expression.

value - the expected value of the property. Can be omitted if the property
is a boolean property (value will be Boolean.TRUE). The test expression is supposed to return
EvaluationResult.TRUE if the property matches the value and EvaluationResult.FALSE
otherwise. The value attribute is converted into a Java base type using the following
rules:

the string "true" is converted into Boolean.TRUE

the string "false" is converted into Boolean.FALSE

if the string contains a dot then the interpreter tries to convert
the value into a Float object. If this fails the string is treated as a
java.lang.String

if the string only consists of numbers then the interpreter
converts the value into an Integer object.

in all other cases the string is treated as a java.lang.String

the conversion of the string into a Boolean, Float, or Integer can
be suppressed by surrounding the string with single quotes. For
example, the attribute value="'true'" is converted into the
string "true"

forcePluginActivation - a flag indicating whether the plug-in contributing the property tester
should be loaded if necessary. As such, this flag should be used judiciously,
in order to avoid unnecessary plug-in activations. Most clients should avoid
setting this flag to true. This flag is only honored if the evaluation context
used to evaluate this expression allows plug-in activation. Otherwise the flag
is ignored and no plug-in loading takes place.

This element is used to perform an equals check of the object in focus. The expression returns
EvaluationResult.TRUE if the object is equal to the value provided by the attribute value. Otherwise
EvaluationResult.FALSE is returned.

value - the expected value. The value provided as a string is converted into
a Java base type using the same rules as for the value attribute of the test expression.

This element changes the object to be inspected for all its child element to the object
referenced by the given variable. If the variable can not be resolved then the expression
will throw an ExpressionException when evaluating it. The children of a with expression
are combined using the "and" operator.

variable - the name of the variable to be used for further inspection. It is up to the evaluator
of an extension point to provide the variable in the variable pool.

This element changes the object to be inspected for all its child element to the object
referenced by the given variable. If the variable can not be resolved then the expression
will throw an ExpressionException when evaluating it. The children of a resolve expression
are combined using the "and" operator.

variable - the name of the variable to be resolved. This variable is then used as the object in focus
for child element evaluation. It is up to the evaluator of an extension point to provide a
corresponding variable resolver (see IVariableResolver) through the evaluation context passed
to the root expression element when evaluating the expression.

args - additional arguments passed to the variable resolver. Multiple arguments are separated
by commas. Each individual argument is converted into a Java base type using the same
rules as defined for the value attribute of the test expression.

This element is used to adapt the object in focus to the type specified by the attribute
type. The expression returns EvaluationResult.NOT_LOADED if either the adapter or the type referenced isn't
loaded yet. It throws an ExpressionException during evaluation if the type name doesn't exist
at all. The children of an adapt expression are combined using the "and" operator.

This element is used to iterate over a variable that is of type java.util.Collection, or a variable that
adapts to org.eclipse.core.expressions.IIterable. If the object in focus is not one of the above then a
CoreException with an ExpressionStatus will be thrown while evaluating the expression.
The child expressions of an iterate expression are combined using the "and" operator.

operator - either "and" or "or". The operator defines how the results of all the child expressions
applied to each child of the Collection or IIterable will be combined and what (if any) short circuit
evaluation will be used. If not specified, "and" will be used.

ifEmpty - the value returned from the "iterate" expression if the collection is empty. If
not specified then EvaluationResult.TRUE is returned when the operator equals "and"
and EvaluationResult.FALSE is returned if the operator equals "or".

This element is used to reference an expression from the org.eclipse.core.expressions.definitions extension point. The expression definition will be evaluated within the current expression element using the current evaluation context.

definitionId - The unique id of an expression from org.eclipse.core.expressions.definitions.

Examples:

This is an example of a strategy being registered for a target definition file type:

Copyright (c) 2017 Rogue Wave Software Inc. and others
This program and the accompanying materials are made available under the terms of the Eclipse Public License 2.0 which accompanies this distribution, and is available at https://www.eclipse.org/legal/epl-v20.html/
SPDX-License-Identifier: EPL-2.0